U.S. patent number 11,259,831 [Application Number 15/787,633] was granted by the patent office on 2022-03-01 for therapeutic ultrasound apparatus and method.
This patent grant is currently assigned to Novuson Surgical, Inc.. The grantee listed for this patent is Novuson Surgical, Inc.. Invention is credited to Daniel Baker, Eric Hadford, Stuart B. Mitchell.
United States Patent |
11,259,831 |
Mitchell , et al. |
March 1, 2022 |
Therapeutic ultrasound apparatus and method
Abstract
Various devices related to a therapeutic ultrasound device for
use during a medical procedure to cauterize tissue are disclosed.
The therapeutic ultrasound device can include an inner tube
assembly and an outer tube assembly. The device can further include
a tissue engagement assembly that is secured to the distal end of
the inner tube and the distal end of the outer tube. The tissue
engagement assembly includes a plurality of transducers configured
to provide therapeutic ultrasound. The device can include a housing
assembly that is secured to the proximal end of the inner tube and
the proximal end of the outer tube. The housing assembly can
include a handle configured to actuate the inner tube relative to
the outer tube to engage and disengage the tissue engagement
assembly.
Inventors: |
Mitchell; Stuart B. (Bothell,
WA), Hadford; Eric (Bothell, WA), Baker; Daniel
(Bothell, WA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Novuson Surgical, Inc. |
Bothell |
WA |
US |
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Assignee: |
Novuson Surgical, Inc.
(Bothell, WA)
|
Family
ID: |
65719037 |
Appl.
No.: |
15/787,633 |
Filed: |
October 18, 2017 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20190083818 A1 |
Mar 21, 2019 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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62560069 |
Sep 18, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B
17/320092 (20130101); A61B 17/295 (20130101); A61N
7/02 (20130101); A61B 17/225 (20130101); A61N
7/022 (20130101); A61B 2090/378 (20160201); A61B
2017/22021 (20130101); A61B 2017/320069 (20170801); A61B
2017/2936 (20130101); A61B 2017/320095 (20170801); A61B
2017/320094 (20170801); A61B 2017/2926 (20130101); A61N
2007/0056 (20130101); A61B 2017/2825 (20130101); A61B
2017/2929 (20130101); A61N 2007/0073 (20130101); A61B
2017/2902 (20130101) |
Current International
Class: |
A61B
17/32 (20060101); A61N 7/02 (20060101); A61B
17/29 (20060101); A61B 17/295 (20060101); A61B
17/225 (20060101); A61N 7/00 (20060101); A61B
17/28 (20060101); A61B 90/00 (20160101) |
Field of
Search: |
;606/27 |
References Cited
[Referenced By]
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Foreign Patent Documents
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2005-505341 |
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2007-525285 |
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Sep 2007 |
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JP |
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2008-515562 |
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May 2008 |
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JP |
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2009-177302 |
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Aug 2009 |
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JP |
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JP |
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WO 2005/092216 |
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WO |
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WO 2007/021958 |
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WO |
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WO 2007/035529 |
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WO 2017/123846 |
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Jul 2017 |
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WO |
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Other References
Invitation to Pay Additional Fees and, Where Applicable, Protest
Fee in PCT Application No. PCT/US18/51215 dated Nov. 8, 2018 in 2
pages. cited by applicant .
International Search Report in PCT/US2006/031414 dated Mar. 26,
2007 (WO 2007/021958). cited by applicant .
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(WO 2007/035529). cited by applicant .
Accord, Ryan E., et al., The Issue of Transmurality in Surgical
Ablation for Atrial Fibrillation, Cardiothoracic Surgery Network;
Aug. 8, 2005. cited by applicant .
Wissler, Eugene H., Pennes' 1948 paper revisited; 50 years of JAP,
American Physiological Society, pp. 35-41; 1998. cited by applicant
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International Patent Application No. PCT/US2018/051215; Int'l
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cited by applicant .
International Patent Application No. PCT/US2018/051215; Int'l
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applicant.
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Primary Examiner: Dvorak; Linda C
Assistant Examiner: Potter; Nils A
Attorney, Agent or Firm: BakerHostetler
Parent Case Text
PRIORITY STATEMENT
This application claims a priority benefit under 35 U.S.C. .sctn.
119 of U.S. Patent Application No. 62/560,069, filed Sep. 18, 2017,
the entirety of which is hereby incorporated by reference herein.
Claims
What is claimed is:
1. A therapeutic ultrasound device for use during a medical
procedure to cauterize tissue, the therapeutic ultrasound device
comprising: an inner tube having a proximal end and a distal end,
wherein the distal end of the inner tube comprises a first
engagement portion configured to receive and secure a first
moveable fastener; an outer tube having a proximal end and a distal
end, wherein the distal end of the outer tube comprises a second
engagement portion configured to receive and secure a second
moveable fastener, and wherein the outer tube is disposed about the
inner tube such that the second engagement portion is aligned with
the first engagement portion; a tissue clamping assembly having a
width less than about 15 millimeters and configured to apply a
clamping force at a target site, wherein the tissue clamping
assembly comprises a first jaw and a second jaw, and a plurality of
acoustic stacks comprising a piezoelectric layer adhered to a
matching layer, wherein the first jaw opposes the second jaw, and
each jaw comprises an opening to receive and removably secure an
acoustic stack, wherein the piezoelectric layer comprises (i) at
least one piezoelectric transducer configured to generate and
propagate ultrasonic waves to provide therapeutic ultrasound, and
(ii) a plurality of slots configured to promote a uniform acoustic
field along a length of the piezoelectric layer, wherein the
matching layer is configured to prevent reflection of ultrasonic
waves by the target tissue; and wherein a distal end of the tissue
clamping assembly is configured to engage with the first engagement
portion of the inner tube and the second engagement portion of the
outer tube; and a housing assembly secured to the proximal end of
the inner tube and the proximal end of the outer tube, wherein the
housing assembly comprises a handle configured to actuate the inner
tube relative to the outer tube and close the tissue clamping
assembly.
2. The therapeutic ultrasound device of claim 1, wherein the first
engagement portion of the inner tube is secured to the tissue
clamping assembly with the first moveable fastener, and wherein the
second engagement portion of the outer tube is secured to the
tissue clamping assembly with the second moveable fastener.
3. The therapeutic ultrasound device of claim 2, wherein the first
jaw and the second jaw of the tissue clamping assembly are
configured to rotate about the second moveable fastener.
4. The therapeutic ultrasound device of claim 3, wherein actuating
the handle in a first direction is configured to move the inner
tube and the attached first moveable fastener to separate the first
jaw and the second jaw, and wherein actuating the handle in a
second direction is configured to move the inner tube and the
attached first moveable fastener to bring the first jaw and the
second jaw adjacent to each other.
5. The therapeutic ultrasound device of claim 1, wherein the outer
tube comprises at least one of double hard stainless steel,
aluminum, titanium, plastic, or carbon fiber.
6. The therapeutic ultrasound device of claim 1, wherein the inner
tube comprises at least one of double hard stainless steel,
aluminum, titanium, plastic, or carbon fiber.
7. The therapeutic ultrasound device of claim 1, wherein the first
jaw and the second jaw are configured to apply any one of about 10
lbs., about 11 lbs., about 12 lbs., about 13 lbs. and about 14
lbs.
8. A therapeutic ultrasound device comprising: an inner tube having
a proximal end and a distal end; an outer tube having a proximal
end and a distal end, wherein the outer tube is disposed about the
inner tube such that the distal end of the inner tube and the
distal end of the outer tube are aligned; an engagement assembly
secured to the distal end of the inner tube and the distal end of
the outer tube, and having a width less than about 15 millimeters,
wherein the engagement assembly is configured to apply an
engagement force to a target and includes a plurality of opposing
acoustic stacks, each comprising a piezoelectric layer adhered to a
matching layer, wherein the piezoelectric layer comprises (i) at
least one piezoelectric transducer configured to generate and
propagate ultrasonic waves to provide therapeutic ultrasound
directed to the target, and (ii) a plurality of slots configured to
promote a uniform acoustic field along a length of the
piezoelectric layer, wherein the matching layer is configured to
prevent reflection of ultrasonic waves by the target tissue; and a
housing assembly secured to the proximal end of the inner tube and
the proximal end of the outer tube, wherein the housing assembly
comprises a handle configured to actuate the inner tube relative to
the outer tube, and wherein actuation of the inner tube relative to
the outer tube is configured to engage and disengage the engagement
assembly.
9. The therapeutic ultrasound device of claim 8, wherein the
engagement assembly is configured to apply at least about 10 pounds
of engagement force to the target.
10. The therapeutic ultrasound device of claim 8, wherein the
engagement assembly comprises a first jaw and a second jaw; wherein
the first jaw and the second jaw are each configured to engage with
a moveable fastener to secure the first jaw to the second jaw; and
wherein at least one of the first jaw and the second jaw is
moveable.
11. The therapeutic ultrasound device of claim 10, wherein the
first jaw and the second jaw of the engagement assembly are
configured to move relative to each other in a scissor-like
movement.
12. The therapeutic ultrasound device of claim 10, wherein the
first jaw and the second jaw of the engagement assembly are
configured to move relative to each other in parallel.
13. The therapeutic ultrasound device of claim 10, wherein the
distal end of the outer tube is engaged with the moveable fastener
to secure the first jaw and the second jaw of the engagement
assembly, and wherein the inner tube is engaged with a distal end
of the first jaw and the second jaw such that movement of the inner
tube in a first direction separates the first jaw and the second
jaw and movement of the inner tube in a second direction brings the
first jaw and the second jaw adjacent to each other.
14. The therapeutic ultrasound device of claim 8, wherein the
engagement assembly engages a target to apply engagement pressure
and therapeutic ultrasound from the at least one transducer to seal
the target.
15. The therapeutic ultrasound device of claim 8, wherein the
engagement assembly engages a target to apply engagement pressure
and therapeutic ultrasound from the at least one transducer to cut
the target.
16. The therapeutic ultrasound device of claim 8, wherein the outer
tube comprises at least one of double hard stainless steel,
aluminum, titanium, plastic, and carbon fiber.
17. The therapeutic ultrasound device of claim 8, wherein the inner
tube comprises at least one of double hard stainless steel,
aluminum, titanium, plastic, and carbon fiber.
18. The therapeutic ultrasound device of claim 8, wherein the
engagement assembly comprises at least one of stainless steel or
ceramics.
19. The therapeutic ultrasound device of claim 8, wherein the
transfer of force from the housing assembly to the engagement
assembly is about 20:1.
20. The therapeutic ultrasound device of claim 8, wherein the
engagement assembly has a width less than about 15 millimeters and
greater than about 3 millimeters.
21. A method of applying therapeutic ultrasound to a target tissue
site, the method comprising: guiding a tissue engagement assembly
to the target tissue site, the tissue engagement assembly
comprising a plurality of opposing acoustic stacks, each comprising
a piezoelectric layer adhered to a matching layer, wherein the
piezoelectric layer comprises (i) at least one piezoelectric
transducer configured to generate and propagate ultrasonic waves to
provide therapeutic ultrasound to the tissue target site, and (ii)
a plurality of slots configured to promote a uniform acoustic field
along a length of the piezoelectric layer, wherein the matching
layer is configured to prevent reflection of ultrasonic waves by
the target tissue; wherein the tissue engagement assembly is
secured to the distal end of an actuation device, and wherein the
actuation device comprises an outer tube disposed about an inner
tube, the outer tube configured to secure the tissue engagement
assembly and the inner tube configured to move relative to the
outer tube to engage and disengage the tissue engagement assembly;
actuating the inner tube in a first direction to engage the tissue
engagement assembly with the target tissue site; applying
engagement pressure to the target tissue site with the tissue
engagement assembly; providing therapeutic ultrasound to the target
tissue site via the at least one transducer; and actuating the
inner tube in a second direction to disengage the tissue engagement
assembly from the target tissue site.
22. The method of applying therapeutic ultrasound to a target
tissue site of claim 21, wherein the therapeutic ultrasound that is
provided to the target tissue site seals tissue at the target
tissue site.
23. The method of applying therapeutic ultrasound to a target
tissue site of claim 21, wherein the therapeutic ultrasound that is
provided to the target tissue site cuts tissue at the target tissue
site.
24. The method of applying therapeutic ultrasound to a target
tissue site of claim 21, wherein the tissue engagement assembly has
a width less than about 15 millimeters.
25. The method of applying therapeutic ultrasound to a target
tissue site of claim 21, wherein the tissue engagement assembly is
configured to apply at least about 10 pounds of engagement force to
the target site.
Description
BACKGROUND
This disclosure relates to methods and apparatus for surgical
procedures that utilize therapeutic ultrasound. Therapeutic
ultrasound refers to the use of ultrasonic waves to induce changes
in tissue state through both thermal effects (e.g., induced
hyperthermia) and mechanical effects (e.g., induced cavitation).
Therapeutic ultrasound can refer to either High Intensity Focused
Ultrasound (HIFU) or Direct Therapeutic Ultrasound (DTU) and can be
employed in both hyper-thermic and cavitational medical
applications, whereas low intensity ultrasound has been used
principally for its cavitation effect. Diagnostic medical
ultrasonic imaging is well known, for example, in the common use of
sonograms for fetal examination.
BRIEF DESCRIPTION OF THE FIGURES
Various embodiments are depicted in the accompanying drawings for
illustrative purposes, and should not be interpreted as limiting
the scope of the embodiments. Furthermore, various features of
different disclosed embodiments can be combined to form additional
embodiments, which are part of this disclosure.
FIG. 1A illustrates an exploded view of a sample therapeutic
ultrasound device.
FIG. 1B illustrates a cross-sectional side view of the sample
therapeutic ultrasound device of FIG. 1A.
FIG. 1C illustrates a side view of internal elements of the sample
therapeutic ultrasound device of FIG. 1A wherein the external
housing is removed.
FIG. 1D illustrates an exploded view of the internal elements shown
in FIG. 1C, namely, an outer tube assembly and an inner tube
assembly, of the sample therapeutic ultrasound device of FIG.
1A.
FIG. 2A illustrates an exploded view of the outer tube assembly of
the sample therapeutic ultrasound device of FIG. 1A.
FIGS. 2B-2C illustrate a plurality of views of a distal end of the
outer tube assembly of the sample therapeutic ultrasound device of
FIG. 1A.
FIG. 2D illustrates a cross-sectional view of a proximal end of the
outer tube assembly of the sample therapeutic ultrasound device of
FIG. 1A.
FIGS. 2E-2H illustrate a plurality of views of an adaptor of the
outer tube assembly of the sample therapeutic ultrasound device of
FIG. 1A.
FIG. 3A illustrates an exploded view of the inner tube assembly of
the sample therapeutic ultrasound device of FIG. 1A.
FIGS. 3B and 3C illustrate a plurality of views of the inner tube
assembly of the sample therapeutic ultrasound device of FIG.
1A.
FIG. 3D illustrates a cross-section of an engagement of various
components of the inner tube assembly of the sample therapeutic
ultrasound device of FIG. 1A.
FIGS. 4A-4F illustrate various views of a tissue engagement
assembly located on a distal end of the sample therapeutic
ultrasound device of FIG. 1A.
FIG. 5A illustrates an exploded view of the tissue engagement
assembly located at the distal end of the sample therapeutic
ultrasound device of FIG. 1A.
FIG. 5B illustrates a prospective view of the tissue engagement
assembly located at the distal end of the sample therapeutic
ultrasound device of FIG. 1A.
FIGS. 5C-5D illustrate cross-sectional views of the tissue
engagement assembly located at the distal end of the sample
therapeutic ultrasound device of FIG. 1A.
FIG. 5E illustrates a cross-sectional view of the distal end of the
sample therapeutic ultrasound device of FIG. 1A located along plane
"5E-5E" as shown in FIG. 5B.
FIG. 5F illustrates a cross-sectional view of the distal end of the
sample therapeutic ultrasound device of FIG. 1A located along plane
"5F-5F" as shown in FIG. 5B.
FIGS. 6A-6B illustrate a first embodiment of an acoustic stack
located in the tissue engagement assembly of the sample therapeutic
ultrasound device of FIG. 1A.
FIG. 6C illustrates an exploded view of a first embodiment of the
acoustic stack of FIGS. 6A-6B.
FIGS. 7A-7B illustrate a second embodiment of the acoustic stack
located in the tissue engagement assembly of the sample therapeutic
ultrasound device of FIG. 1A.
FIG. 7C illustrates an exploded view of a second embodiment of the
acoustic stack of FIGS. 7A-7B.
FIGS. 8A-8B illustrate a third embodiment of the acoustic stack
located in the tissue engagement assembly of the sample therapeutic
ultrasound device of FIG. 1A.
FIG. 8C illustrates an exploded view of the third embodiment of the
acoustic stack of FIGS. 8A-8B.
FIG. 9A illustrates a cross-sectional view of an embodiment of a
transducer formed from one of the jaws of the tissue engagement
assembly of the sample therapeutic ultrasound device of FIG. 1A,
and configured to receive any of the disclosed acoustic stacks
illustrated in FIGS. 6A-6B, 7A-7B, and 8A-8B.
FIG. 9B illustrates a cross-sectional view of another embodiment of
a transducer formed from one of the jaws of the tissue engagement
assembly of the sample therapeutic ultrasound device of FIG. 1A,
and configured to receive any of the disclosed acoustic stacks
illustrated in FIGS. 6A-6B, 7A-7B, and 8A-8B.
FIG. 10 illustrates the relationship between jaw clamp force over a
range of jaw opening angles for straight and curved slots in the
ears of the pair of jaws.
FIG. 11 illustrates the relationship between the velocity of sound
in tissue and temperature.
FIG. 12A illustrates the relationship between the maximum
temperature and acoustic energy with time fixed.
FIG. 12B illustrates the relationship between maximum temperature
and time with power and intensity fixed.
FIG. 12C illustrates the relationship between the maximum
temperature and intensity with time fixed.
FIG. 12D illustrates the time required to reach a given temperature
at a specific power.
FIG. 13A-13D illustrate the use of the voltage standing wave ratio
to determine end of treatment.
FIG. 14 illustrates an example of the relationship between energy
and clamping force as it relates to sealing and dividing
tissue.
DETAILED DESCRIPTION
Various therapeutic ultrasound apparatus and methods are disclosed
that may be employed to achieve one or more desired improvements in
the field of surgery. For purposes of presentation, certain
embodiments are disclosed with respect to a surgical therapeutic
ultrasound apparatus and methods of use, but the disclosed
embodiments can be used in other contexts as well. Indeed, the
described embodiments are examples only and are not intended to
restrict the general disclosure presented and the various aspects
and features of this disclosure. The general principles described
herein may be applied to embodiments and applications other than
those discussed herein without departing from the spirit and scope
of the disclosure. This disclosure should be accorded the widest
scope consistent with the principles and features that are
disclosed or suggested herein.
Although certain aspects, advantages, and features are described
herein, it is not necessary that any particular embodiment include
or achieve any or all of those aspects, advantages, and features.
For example, some embodiments may not achieve the advantages
described herein, but may achieve other advantages instead. No
feature, component, or step is necessary or critical.
Overview
In the U.S. alone, several hundred thousand surgical procedures are
performed each year that involve the removal of tissue, or a
portion of an organ because of some pathology involving the tissue.
Many of these procedures remove benign or malignant tumors.
Although a significant percentage of such tissue and organ removal
procedures employ conventional surgical techniques, a major effort
has been directed to replacing conventional surgical techniques
with minimally invasive surgical techniques to reduce morbidity.
However, performing such surgery using minimally invasive
instruments requires significant training and advanced skills on
the part of the operating physician. Disclosed below are methods
and apparatus that are minimally invasive and are easier to
implement than those currently used.
During invasive surgery, an obvious problem is bleeding. In a
retrospective cohort study involving 600 hospitals, bleeding
complications occurred in approximately 45% of surgical procedures,
increasing hospitalization by about 125% (7 days on average), and
increasing hospital costs by .about.$7,500 per patient (per
procedure). Bleeding also significantly contributes to the majority
of the approximately 120,000 trauma deaths per year. In trauma, 30%
to 40% of deaths are related to uncontrolled bleeding. Blood
transfusions (planned or unexpected) and reoperations are used to
mitigate bleeding and avert death. These procedures can be costly
and are associated with complications. Blood transfusion can lead
to nosocomial infection, immunosuppression, transfusion-related
acute lung injury, and even death. Reoperations lead to increased
costs and longer hospitalization. As a result, many needless
bleeding complications occur with current technologies resulting in
increased hospitalization times, hospital costs, and patient
deaths. To reduce bleeding, surgical techniques are needed to
provide for fast and robust control of bleeding--allowing surgical
procedures without hemorrhaging as well as rapidly controlling
bleeding in trauma.
The most common surgical technique in the state of the art for
coagulating bleeding vessels is to apply an electrical cauterizing
probe to the bleeding site. However, if a bleeding vessel is more
than about 1.5 millimeters (mm) in diameter, or an organ which is
highly vascularized and where uncontrolled hemorrhage is the
primary cause of death, direct electrical cauterization is
ineffective. In such instances, a more complicated technique of
clamping of a large blood vessel and electrical cauterization via
the clamp or with laser light can instead be used. However, problem
frequently faced, that is not solved with either electrical or
laser cauterization techniques, is the control of a rapidly
bleeding vessel because the blood egress is often sufficiently
large enough to carry the heat away before coagulation or tissue
necrosis is accomplished. Particularly in surgery involving organs,
neither electrical or laser cauterization is effective. Moreover,
organs such as the liver and the spleen are subject to bleeding
profusely from cracks in the parenchyma, which is usually diffuse
and non-pulsatile due to the large number of small vessels.
The disclosed methods and apparatus can be used to assist
emergency, specialty, and general physicians in performing
surgeries rapidly and without common complications associated with
bleeding. This can reduce surgical and anesthesia time and
minimizes blood product usage, which can improve patient outcomes
and decrease healthcare costs.
Therapeutic Ultrasound Overview
In view of the surgical procedures described above, disclosed are
methods and apparatus for enabling surgical procedures relating to
bloodless surgery and for stemming hemorrhaging. For example,
therapeutic ultrasound can be used to form cauterized tissue
regions prior to surgical incision. This can be particularly
effective for use in surgical lesion removal or resecting highly
vascularized tissue.
Generally, therapeutic ultrasound is a modality in interventional
medicine that is based on the delivery of acoustic energy at
ultrasonic frequencies within the human body with the precise
intent of eliciting well defined biological effects. These
biological consequences are induced, or mediated, primarily by two
mechanisms of action: thermal effects and mechanical effects.
Thermal effects derive from the absorption of the vibrational
acoustic energy by the tissue (through relaxation and
thermos-viscous processes) and its conversion into heat which, in
turn, generates a temperature increase in the exposed region.
Mechanical effects are due to the large gradients in pressure
associated with the oscillatory nature of the ultrasound waves
which produce high stress and strain forces as experienced by the
medium. Additionally, in the presence of gas bodies within the
ultrasonic field of action, cavitation may also occur. Cavitation
is the dynamic activity of gas bubbles which grow and collapse
under the influence of an acoustic field. It can be stable and
sustained, when the bubbles oscillate in phase with the acoustic
wave without being destroyed, in which case they produce
significant shearing forces and additional viscous heating; or it
can be inertial and transient, when new gas bubbles are nucleated
from dissolved gas in the tissue and they rapidly grow and
violently collapse before dissolving again, in which case they
produce extremely high mechanical stresses, shock waves, and strong
fluid microjets.
One type of therapeutic ultrasound is High Intensity Therapeutic
Ultrasound (also commonly referred to as HIFU-High Intensity
Focused Ultrasound and FUS-Focused Ultrasound Surgery). HIFU is
mainly directed towards the very rapid heating of tissue above the
protein denaturization and cell coagulative necrosis thresholds and
is intended to create a permanent, irreversible, and localized
thermal lesion within the tissue or to cauterize a bleeding vessel.
This results in the concentration of the majority of the available
input power in a focal volume of the order of 1-2 wavelengths in
cross section and about 5-7 wavelengths in length (approximately
1.5.times.1.5.times.10 mm3 for a 1 MHz system) with extremely high
energy densities in the order of hundreds to thousands of
Watts/cm.sup.2. This high-energy concentration allows for rapid
temperature rise in the focal volume such that cell necrosis and
ablation is achieved within 1-2 seconds. Although energy densities
at the face of the ultrasound applicator are orders of magnitude
lower than at the focus, because of the multiple unit lesions
necessary for a full treatment, the ultrasound energy deposition at
the skin interface and immediately below compounds during the whole
application and typically unwanted skin burns and subcutaneous
damage occur.
HIFU can be employed in both hyperthermic and cavitational medical
applications. HIFU waves, for example, can be propagated into
tissue toward a discrete focal region, and the accumulation of the
resultant harmonic frequencies can induce rapid heating at the
focal region that ablates, necrotizes, and/or otherwise damages the
tissue. In a clinical setting, HIFU-induced heating can be used to
treat benign and malignant tumors (e.g., in the brain, uterus,
prostate, liver, etc.) and/or occlude blood vessels (e.g., to
induce hemostasis of internal bleeds, intervene in fetal blood
sharing anomalies, and confine tumor blood supply). During HIFU
therapy and/or other treatments that form heat-induced lesions,
image guidance and treatment monitoring (e.g., temperature
monitoring) can be used for controlling and optimizing the
parameters of the treatment and assessing its efficacy.
In HIFU hyperthermia treatments, the intensity of ultrasonic waves
generated by a highly focused transducer increases from the source
to the region of focus where it can reach a very high temperature,
(e.g., 98.degree. Centigrade). The absorption of the ultrasonic
energy at the focus can induce a sudden temperature rise of tissue
which can be as high as between 100-200.degree. K/sec. Such a
dramatic increase in temperature can cause the ablation of target
cells at the focal region. The focal region dimensions are referred
to as the depth of field, and the distance from the transducer to
the center point of the focal region is referred to as the "depth
of focus."
Thus, HIFU hyperthermia treatments can result in necrotization of
an internal lesion without damage to the intermediate tissues. The
disclosed methods and apparatus using HIFU are a non-invasive
surgical technique because the ultrasonic waves provide a
non-effective penetration of intervening tissues, yet with
sufficiently low attenuation configured to deliver energy to a
small focal target volume. For example, a very high frequency,
e.g., 30 MHz wave would be absorbed nearly immediately by the first
tissue it is applied to. Yet, lower frequencies, e.g., 30 KHz-60
KHz, are associated with cavitation effects because of the longer
rarefaction time periods, allowing gaseous vapor formation. Thus,
the effect of ultrasound energy is quite different at a frequency
of 30 KHz versus 30 MHz. Moreover, the rate of heat generation in
tissue is proportional to the absorption constant. For example, for
the liver, the attenuation constant is approximately 0.0015 at 30
KHz, but is approximately 0.29 at 3 MHz. Therefore, all other
variables being equal, the heat generated in liver tissue is about
190 times greater at 3 MHz than at 30 KHz. While this means
hyperthermia can be achieved more quickly and to a much greater
level with high frequencies, the danger to intervening tissue
between the transducer and the focal region is much more prevalent.
Therefore, by instead using a lower frequency, energy can be
delivered to a small focused target volume of tissue without
damaging intervening tissues.
Direct Therapeutic Ultrasound (DTU), another type of therapeutic
ultrasound, refers to the use of direct therapeutic ultrasonic
waves to induce changes in tissue state through both thermal
effects (e.g., induced hyperthermia) and mechanical effects (e.g.,
induced cavitation). DTU can be used to directly lock and compress
vascularized tissue, up to several millimeters thick, before being
coagulated and sealed by the ultrasound energy in seconds. While
still based on ultrasonically mediated thermal mechanisms, in
contrast to traditional high intensity therapeutic ultrasound, this
approach utilized significantly lower power densities (in the order
of 5-30 W/cm.sup.2) and a uniform distribution of the ultrasound
energy throughout the full treatment domain, thus avoiding
generation of localized hot spots and collateral damage. In fact,
the treatment region is fully contained and well-defined within the
opposite jaws of the device where a uniform planar standing wave is
generated between the two opposing ultrasound transducers, quickly
dissipating away from the applicators edges resulting in minimal
thermal spreading.
This type of application is intended for open and
minimally-invasive laparoscopic surgery, and compared to standard
HIFU applications does not require additional targeting and
monitoring systems and does not suffer from similar safety concerns
in terms of on-path unintended injury and/or cavitation effects.
This is due to the fact that the propagation path is only few
millimeters long and fully restricted within the applicator
footprint thus avoiding significant energy diffraction; peak
rarefactional pressure are well below the in-vivo threshold for
cavitation processes; and the tissue is subject to significant
overpressure from the clamping device, additionally inhibiting the
inception of bubble formation and cavitation.
Disclosed is also an apparatus configured to emit therapeutic
ultrasound (whether HIFU or DTU) from one or more transducers that
are attached to a minimally invasive surgical instrument. Such a
tool can provide sufficient clamping or engagement pressure to
collapse blood vessels' walls, so that they will be sealed by the
application of the DTU, and by the resulting thermal ablation and
tissue cauterization. Such an instrument can provide feedback to
the user that the lesion is completely transmural and that blood
flow to the region distal of the line of thermal ablation has
ceased. In some embodiments, instruments having opposed arms can be
configured for use in conventional surgical applications.
Instruments can be implemented with transducers on only one arm,
and an ultrasound reflective material disposed on the other
arm.
The disclosure provided herein describes apparatus and methods
related to performing surgical procedures with a minimum of
bleeding. In some embodiments, such procedures are minimally
invasive procedures (e.g., laparoscopy, endoscopy, etc.). In other
embodiments the disclosed procedures and apparatus can also be
applied to more invasive surgical procedures. The disclosed
apparatus and methods can enable removal of undesirable tissues,
such as benign and malignant tumors, from the body without fear of
uncontrolled bleeding that can result from such procedures using
conventional techniques.
In particular, disclosed is an apparatus for sealing or cutting
tissue having a small engagement region such that the apparatus can
be used in minimally invasive procedures. As will be discussed in
detail, although the apparatus comprises a small engagement region,
the device is configured to provide sufficient clamping force and
power to the target site to effectively cauterize tissue in a short
amount of time.
Therapeutic Ultrasound Device
FIGS. 1A-1D illustrate a plurality of views of a sample therapeutic
ultrasound device 100 formed in accordance with the present
disclosure. FIG. 1A illustrates an exploded view of the proximal
end 104 of the therapeutic ultrasound device 100 such that the
interior components of the therapeutic ultrasound device 100 are
visible. FIG. 1B illustrates a cross-sectional view of the
therapeutic ultrasound device 100 showing the arrangement of the
internal components of the therapeutic ultrasound device 100 within
the housing 110.
The disclosed therapeutic ultrasound device 100 is configured to
use focused ultrasound transducers or unfocused ultrasound
transducers integrated with a hemostatic clamping instrument. When
deployed, the ultrasound energy ablates the tissue contained
between the heads, thereby forming a hemostatic plane of
cauterization. This allows surgeons to remove tumors, tissue, or
organs without bleeding and also provides a method to rapidly
control bleeding in trauma situations, significantly reducing the
risk of bleeding complications and reducing trauma death due to
exsanguination. This technology is applicable to open and
laparoscopic procedures. As will be discussed in more detail below,
the disclosed therapeutic ultrasound device 100 can cauterize
tissues over 3 cm thick and can assess whether treatment has been
completed effectively.
As an overview, the therapeutic ultrasound device 100 may include a
distal end 102 and a proximal end 104, wherein the distal end 102
includes an engagement portion and the proximal end 104 includes a
user actuation mechanism. For example, the proximal end 104 of the
therapeutic ultrasound device 100 includes a housing 110 that
secures the internal components of the therapeutic ultrasound
device 100. The housing 110 can include a first half (e.g., left
housing 110a) and a second half (e.g., right housing 110b) that can
be secured together using a plurality of first fasteners 114 and
second fasteners 116. As shown in FIG. 1A, the plurality of first
fasteners 114 and second fasteners 116 are inserted through the
plurality of openings 112 through both halves of the housing 110.
In some examples, the first fasteners 114 are screws and the second
fasteners 116 are inserts that are configured to engage with each
other and secure both halves of the housing 110, however, those
skilled in the art will recognize that other types of fasteners may
be used without departing from the scope of the present disclosure.
The first fasteners 114 and the second fasteners 116 can comprise
any structures that secure the housing 110 to the therapeutic
ultrasound device 100.
As shown in FIG. 1A, the housing 110 can be configured to secure
the handle 120 along with a plurality of other components that are
configured to actuate the therapeutic ultrasound device 100.
The therapeutic ultrasound device 100 can include a latch guide
130. As shown in FIG. 1A, the latch guide 130 can comprise a first
portion 130a and second portion 130b that are configured to provide
a path for the spring latch to travel. This can allow the lever to
be "latched" in a closed position. This can ensure that the tissue
is compressed and held during treatment. In some examples, the two
halves of the latch guide 130 are configured to provide a
symmetrical path, thereby distributing the forces on the latch
evenly when the latch is latched.
In some embodiments, the therapeutic ultrasound device 100 includes
a connector 140 and cable 150 that are configured to provide power
to the therapeutic ultrasound device 100. As will be discussed in
more detail, the connector 140 and the cable 150 are configured to
provide power to the plurality of transducers located in the tissue
engagement assembly 400 through a plurality of wires and/or cables.
The tissue engagement assembly 300 may also be referred to herein
as a "jaw" assembly or "clamping" assembly
FIGS. 1A and 1B also illustrate a handle 120 located at the
proximal end 104 of the therapeutic ultrasound device 100. As shown
in FIG. 1B, the handle 120 may extend out from the housing 110 to
allow the user to grip the handle 120 with his/her fingers. In some
embodiments, the handle 120, along with the housing 110, provides a
comfortable and ergonomic fit for the hand of the user. For
example, the palm of the user can rest on the exterior of the
proximal end of the housing 110 and the thumb of the user can curl
about the width of the base of the housing 110. The remaining
fingers of the user can be configured to fit in the opening of the
handle 120 such that the user can pull back and release the handle
120.
The handle 120 can be configured to actuate the movement of a jaw
assembly 400 located on the distal end 102 of the therapeutic
ultrasound device 100. FIG. 1C illustrates the therapeutic
ultrasound device 100 with the proximal end 104 of the therapeutic
ultrasound device 100 with the housing 110 removed. As shown, the
proximal end 104 of the therapeutic ultrasound device 100 can
include a spring 350 disposed about the spring guide 352 adjacent
to the handle 120. In some examples, the spring 350 and the spring
guide 352 allow for the handle 120 to retract and return to its
original position. In some embodiments, the spring 350 and the
spring guide 352 are configured to allow the user to latch the
handle 120 such that the jaw assembly 400 remains clamped on the
tissue. Subsequent squeezing of the handle 120 can be unlatch the
handle to allow the spring to follow the spring guide 352 while the
handle 120 returns to a first position wherein the jaw assembly 400
is opened. In some embodiments, the handle 120 can be configured to
include a memory chip (not illustrated). The memory chip can be
configured to store operating parameters for the therapeutic
ultrasound device 100.
As will be discussed in more detail below, engagement of the handle
120 can be configured to move the inner tube assembly 300 (shown in
FIG. 1D) relative to the outer tube assembly 200. In some
embodiments, the handle 120 is adjacent to the rotation mechanism
220 which is configured to allow the jaw assembly 400 to be rotated
about the longitudinal axis. In some embodiments, the rotation
mechanism 220 can allow rotation through .+-.175 degrees about the
longitudinal axis.
FIG. 1D illustrates an exploded view of the therapeutic ultrasound
device 100 with the housing 110 removed. As will be discussed in
turn below, the therapeutic ultrasound device 100 can include an
outer tube assembly 200, an inner tube assembly 300, and a jaw
assembly 400.
As a brief overview, the outer tube assembly 200 can be disposed
over the inner tube assembly 300. The outer tube assembly 200 can
include an outer tube 206 and an adaptor 210 located at a proximal
end 204. In some embodiments, the adaptor 210 is configured to be
attached to the rotation mechanism 220. The adaptor 210 can be
configured to enable the therapeutic ultrasound device 100 to
accommodate an outer tube 206 and/or an inner tube 308 having
varying diameters without needing to redesign the size and
configuration of the attached handle assembly and other internal
mechanisms of the therapeutic ultrasound device 100.
The inner tube assembly 300 can include an inner tube 308 and a
connector 330 located at a proximal end 304. As shown in FIG. 1D,
the connector 330 can be attached to the handle assembly. As will
be discussed in more detail below, the outer tube 206 and the
adaptor 210 are disposed over the inner tube 308 and the connector
330 respectively. The outer tube assembly 200 can be secured to the
inner tube assembly 300 using a plurality of fasteners. In some
embodiments, the plurality of fasteners comprise a retaining pin
230 and a retaining ring 232; however, as noted above the fasteners
can comprise any shape or structure without departing from the
scope of the present disclosure.
As shown in FIG. 1D, the jaw assembly 400 can be located at the
distal end 102 of the therapeutic ultrasound device 100. As will be
discussed in more detail below, the jaw assembly 400 can include a
top jaw 402 and a bottom jaw 404. The top jaw 402 and the bottom
jaw 404 can be secured to the distal end 202 of the outer tube 206
and the distal end 302 of the inner tube 308 using a pivot pin 460
and an inner tube pin 470. In some embodiments, the jaw assembly
400 can include a bushing 480 to secure the pivot pin 460 in place
and to maintain the space between ears 420 of the top jaw 402 and
the bottom jaw 404. In some examples, the bushing 480 can be
configured to prevent rotation of the top jaw 402 and the bottom
jaw 404 within the jaw assembly 400.
The jaw assembly 400 can be secured to the outer tube 206 and the
inner tube 308 such that withdrawal or advancing of the inner tube
308 relative to the outer tube 206 will cause the top jaw 402 and
the bottom jaw 404 of the jaw assembly 400 to open and close. As
noted above, and as will be discussed in more detail below, the
engagement of the handle 120 in a first direction will case
movement of the inner tube 308, relative to the outer tube 206, in
the first direction. This can cause the jaw assembly 400 to open.
Similarly, release of the handle 120 in a second direction can
cause movement of the inner tube 308, relative to the outer tube
206, in the second direction. This can cause the jaw assembly 400
to close.
Outer Tube Assembly
FIGS. 2A-2G illustrate various embodiments of the outer tube
assembly 200. FIG. 2A illustrates an exploded view of certain
components of the outer tube assembly 200; FIGS. 2B-2C illustrate
the distal end 202 of the outer tube 206; FIG. 2D illustrates the
proximal end 204 of the outer tube assembly 200; and FIGS. 2E-2H
illustrate a plurality of views of the adaptor 210.
As discussed above, the outer tube assembly 200 can include the
outer tube 206, the adaptor 210, and the rotation mechanism 220. As
shown in FIG. 2A, a proximal end of the outer tube 206 can be
secured to the adaptor distal end 212 and the adaptor proximal end
214 can be attached to the rotation mechanism 220. In some
embodiments, the rotation mechanism 220 can comprise any material
such as plastic, metal, rubber, etc.
As will be discussed in more detail below, the jaw assembly 400 can
have a width ranging from 3 mm to 10 mm. In some embodiments, the
jaw assembly 400 can have a width ranging up to 15 mm. The jaw
assembly 400 should therefore be configured to apply sufficient
clamping or engagement force to the target tissue in order to
generate sufficient force for treatment. In some embodiments, this
can be 10-14 lbs. of clamping force at the jaw assembly 400. In
some embodiments, the clamping force at the jaw assembly 400 can be
less than 10 lbs., between 10-11 lbs., between 11 lbs.-12 lbs.,
between 12 lbs.-13 lbs., between 13 lbs.-14 lbs., or greater than
14 lbs. In some embodiments, the clamping force at the jaw assembly
400 can be any of 10 lbs., 11 lbs., 12 lbs., 13 lbs., or 14 lbs. To
translate the force required for the device, the outer tube 206 can
comprise a material that is configured to withstand these forces.
For example, the outer tube 206 can comprise double hard stainless
steel tubing, aluminum, titanium, plastic, carbon fiber, etc. In
some examples, the adaptor 210 can comprise a material that is
configured to withstand these forces. For example, the adaptor 210
can comprise double hard stainless steel tubing, aluminum,
titanium, plastic, carbon fiber, etc. The outer tube 206 and the
adaptor 210 will be discussed in turn.
FIGS. 2B-2C illustrate the distal end 202 of the outer tube 206.
The distal end 202 of the outer tube 206 can include a yoke 240
that includes a pair of arms. Each of the pair of arms of the yoke
240 can include an opening 242 and a slot 244. As shown in FIG. 1D,
a pivot pin 460 can be configured to fit through the opening 242
and the inner tube pin 470 can be configured to move along the slot
244. As will be discussed in more detail below, movement of the
inner tube pin 470 along the slot 244 can be configured to open and
close the jaw assembly 400.
FIG. 2D illustrates the proximal end 204 of the outer tube assembly
200. The proximal end 204 of the outer tube assembly 200 can
include the adaptor 210 having a distal end 212 and a proximal end
214. In some embodiments, the distal end 212 of the adaptor 210 is
disposed over the proximal end of the outer tube 206. In some
examples, the proximal end 214 of the adaptor 210 is located within
the rotation mechanism 220. FIGS. 2E-2H illustrates a plurality of
views of the adaptor 210. A proximal end 214 of the adaptor 210 can
include a plurality of proximal grooves 216. In some examples, the
proximal grooves 216 are configured to lock into a rotation knob.
This can allow the user to rotate the tip of the therapeutic
ultrasound device 100 (e.g., the jaw assembly 400).
Inner Tube Assembly
FIGS. 3A-3D illustrate various embodiments of the inner tube
assembly 300. FIG. 3A illustrates an exploded view of the
components of the inner tube assembly 300; FIG. 3B-3C illustrates a
plurality of views of the distal end 302 and proximal end 304 of
the inner tube assembly 300; and FIG. 3D illustrates a
cross-sectional view of the intersection of the components of the
inner tube assembly 300.
As shown in FIG. 3A, the inner tube assembly 300 can include the
inner tube 308, a spacer 310, and a connector 330. In some
embodiments, the proximal end of the inner tube 308 is configured
to engage with the spacer 310 and the distal end of the connector
330. In some examples, the inner tube 308, spacer 310 and connector
330 comprise a material that is configured to withstand these
forces. For example, any of the inner tube 308, spacer 310, and
connector 330 can comprise double hard stainless steel tubing,
aluminum, titanium, plastic, carbon fiber, etc. In some
embodiments, the inner tube and the outer tube can be flexible or
articulating. In some examples, the inner tube assembly 300 can be
hollow to allow cables and/or wires to run from the distal end 102
to the proximal end 104 of the device.
As discussed with regard to the outer tube 206, the jaw assembly
400 can be configured to apply sufficient clamping or engagement
pressure to the target tissue in order to generate sufficient force
for treatment. To translate the force required for the device, the
inner tube 308 can comprise a material that is configured to
withstand these forces. For example, the inner tube 308 can
comprise double hard stainless steel tubing, aluminum, titanium,
plastic, carbon fiber, etc. In some embodiments, instead of a
hollow tube, the inner tube 308 can instead comprise a solid pull
rod (e.g., a rectangular pull rod). In examples where the inner
tube 308 is solid instead of hollow, traces (rather than cables or
wires) can be used to provide power to the distal end 102 of the
device.
As seen in FIG. 3A, the proximal end of the inner tube 308 can
include a plurality of openings 306. Similarly, the spacer 310 can
include a plurality of openings 312 and the distal end of the
connector 330 can include a plurality of distal openings 336. In
some examples, the spacer 310 can be disposed over the proximal end
of the inner tube 308 such that the plurality of openings 306 of
the inner tube 308 aligns with the plurality of openings 312 of the
spacer 310. In some embodiments, the spacer 310 is configured to
provide an interference fit between the inner diameter of the
connector 330 and the outer diameter of the inner tube 308. In some
embodiments, the distal end of the connector 330 can be disposed
over the spacer 310 and the proximal end of the proximal end of the
inner tube 308. In some examples, the plurality of distal openings
336 of the connector 330 are configured to align with the plurality
of openings 312 of the spacer 310 and the plurality of openings 306
at the proximal end of the inner tube 308.
FIG. 3D illustrates a cross section of the inner tube assembly 300
and an embodiment of the connection between the inner tube 308,
spacer 310, and a connector 330. As noted above, the plurality of
openings 306, 312, 336 can be aligned and secured by fasteners. In
some embodiments, the fasteners securing the inner tube 308, spacer
310, and the connector 330 are a plurality of dowel pins 320. In
some examples, the inner tube 308, spacer 310, and the connector
330 can be bolted, welded, screwed together, or glued.
In some embodiments, the inner tube assembly 300 can include the
connector 330. As noted above, the connector 330 can be configured
to secure the inner tube 308 with the proximal end 104 of the
therapeutic ultrasound device 100 (e.g., the handle 120). In some
examples, the proximal end of the inner tube assembly 300 and the
outer tube assembly 200 is configured to interface with a device
(e.g., other than the handle 120) that is configured to actuate the
jaw assembly 400. For example, this can include a robotic
articulating arm such that the therapeutic ultrasound device 100
can be used in a variety of applications (e.g., endoluminal,
laparascopic, thorascopic procedures).
As noted above, the connector 330 can include a plurality of distal
openings 336 at the distal end of the connector 330, a slot 334,
and a proximal opening 332 at the proximal end of the connector
330. In some examples, the slot 334 is configured to allow the
inner tube 308 of the inner tube assembly 300 to translate through
the therapeutic ultrasound device 100. The retaining pin 230 can be
held in place by the proximal opening 332 and fit into the slot 334
of the connector 330. In some embodiments, the proximal end of the
connector 330 is free floating.
As noted above, in some embodiments, the distal end 302 of the
inner tube assembly 300 can include a yoke 340 comprising a pair of
arms. In some examples, each of the pair of arms of the yoke 340
includes an opening 342. In some embodiments, the opening 342 is
configured to receive the inner tube pin 470.
As will be discussed in more detail below, the outer tube 206 can
disposed over the inner tube 308 such that the yoke 240 of the
outer tube 206 is disposed about the yoke 340 of the inner tube
308. In some examples, the openings 342 and the engaged inner tube
pin 470 of the distal end 302 of the inner tube 308 are aligned
with the slot 244 of the distal end 202 of the outer tube 206. This
can allow the distal end 302 of the inner tube 308 to move the
inner tube pin 470 within the slot 244 of the distal end 202 of the
outer tube 206.
Jaws and Jaw Assembly
FIGS. 4A-4F illustrate an embodiment of individual jaws of the jaw
assembly 400. Although only half of the jaw assembly 400 is
illustrated in FIGS. 4A-4F, the jaw illustrated in FIGS. 4A-4F can
describe the top jaw 402 and/or the bottom jaw 404.
In some embodiments, the jaws 402, 404 include an ear 420 on the
proximal end 408 of the jaw 402, 404 and a body 430 on the distal
end 406 of the jaw 402, 404. The jaw 402, 404 can include an
opening 422 adjacent to the ears 420 and between the ear 420 and
the body 430. As will be discussed in more detail below, the
opening 422 can be configured to receive the pivot pin 460 such
that the jaw 402, 404 can rotate about the pivot pin 460. In some
embodiments, the jaw 402, 404 can be comprised of stainless steel
or ceramics. In some examples, the jaws 402, 404 can have a width
between 3 mm and 10 mm. In some embodiments, the jaws 402, 404 can
have a width between 1 mm and 15 mm. In some embodiments, the jaws
402, 404 can have any of the widths of 1 mm, 2 mm, 3 mm, 4 mm, 5
mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, and
15 mm. In some embodiments, the jaws 402, 404 can have a length
between 5 mm and 100 mm. In some embodiments, the jaws 402, 404 can
have a length between any of the ranges of 5 mm-10 mm, 10 mm-15 mm,
15 mm-20 mm, 20 mm-25 mm, 25 mm-30 mm, 30 mm-35 mm, 35 mm-40 mm, 40
mm-45 mm, 45 mm-50 mm, 50 mm-55 mm, 55 mm-60 mm, 60 mm-65 mm, 65
mm-70 mm, 70 mm-75 mm, 75 mm-80 mm, 80 mm-85 mm, 85 mm-90 mm, 90
mm-95 mm, or 95 mm-100 mm. In some embodiments, the jaws 402, 404
can have any of the lengths of 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30
mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm,
80 mm, 85 mm, 90 mm, 95 mm, and 100 mm.
In some embodiments, the ear 420 includes a slot 424. The slot 424
can be curved (as shown in FIG. 4A), straight, or any other
configuration. The slot 424 can be configured to receive the inner
tube pin 470. As will be discussed in more detail below, movement
of the inner tube pin 470 within the slot 424 can be configured to
cause the pair of jaws 402, 404 of the jaw assembly 400 to move
(e.g., open and close).
In some embodiments, the body 430 comprises an opening 434
configured to receive an acoustic stack (not shown). As shown in
FIGS. 4A and 4E, the opening 434 can be rectangular in shape;
however, the opening 434 can be any shape so long as it can receive
and secure an acoustic stack. In some embodiments, the body 430
forms a shell 432. As will be discussed in more detail below, the
shell 432 of the body 430 can be configured to provide an
air-pocket for a transducer formed with the acoustic stack.
The base of the body 430 can further include an opening 490. The
opening 490 can be configured to allow a cable (not illustrated) of
the acoustic stack to be threaded through the opening 490. The
cable can then be run through the outer tube assembly 200/inner
tube assembly 300 where it is attached to the cable 150 (as shown
in FIG. 1A). In this way, a power source can be provided to the
acoustic stack to power the therapeutic ultrasound device 100.
In some embodiments, the distal end 406 of the jaw 402, 404
includes teeth 410. For example, as shown in FIGS. 4A-4E, the teeth
410 can be formed as wave-like folds in the distal end 406 of the
jaw 402, 404 adjacent to the body 430. In other embodiments, the
teeth 410 are formed along the edge of the distal end 406 of the
jaw 402, 404 or along the entire perimeter of the body 430. The
teeth 410 can have any shape or configuration, such as serrated,
triangular, needle-like, etc. As well, the teeth 410 can be located
on one or both of the jaws 402, 404. In some embodiments, as the
jaw assembly 400 closes on the target tissue, the tissue can be
inclined to move out of place. The teeth 410 are therefore
configured to engage with and retain the target tissue as the jaw
assembly 400 clamps downward.
FIGS. 5A-5D detail an example of the connection between the jaw
assemblies 400 on the distal end 102 of the therapeutic ultrasound
device 100. As discussed above, the jaw assembly 400 can be
assembled to engage with the distal end 202 of the outer tube 206
and the distal end 302 of the inner tube 308. The jaw assembly 400
illustrated in FIGS. 5A-5D includes an acoustic stack 500 with a
cable 440. In some examples, the proximal end of the jaw assembly
400 is configured to interface with a device (e.g., other than the
distal end 202 of the outer tube 206 and the distal end 302 of the
inner tube 308) that is configured to actuate the jaw assembly 400.
For example, this can include a robotic articulating arm such that
the therapeutic ultrasound device 100 can be used in a variety of
applications (e.g., endoluminal, laparascopic, thorascopic
procedures).
As discussed above, the outer tube 206 can be disposed over the
inner tube 308 such that the pair of arms of the yoke 340 of the
inner tube 308 are generally aligned with the pair of arms of the
yoke 240 of the outer tube 206. This can be better seen in the
cross-sectional view of FIGS. 5C and 5D where the outer tube 206 is
disposed over the inner tube 308. To allow the inner tube 308 to
fit within and move relative to the outer tube 206, the diameter of
the inner tube 308 can be less than the outer tube 206. For
example, the inner tube 308 can have a diameter of 0.103 inches and
the outer tube 206 can have a diameter of 0.133 inches.
As seen in FIGS. 5A-5D the yoke 240 of the outer tube 206 and the
yoke 340 of the inner tube 308 are spaced apart to allow the ears
420 of the jaw assembly 400 to fit between. In some embodiments,
the pair of arms of the yoke 240 and the yoke 340 are sufficiently
long such that there is clearance to allow the ears 420 of the top
jaw 402 and the bottom jaw 404 to rotate freely about the pivot pin
460.
As discussed above, each of the pair of arms of the yoke 240 of the
outer tube 206 can include an opening 242 and a slot 244. These
openings, along with the opening 342 located in each of the pair of
arms of the yoke 340 of the inner tube 308, are configured to
retain and move the top jaw 402 and the bottom jaw 404 of the jaw
assembly 400. As noted above, in some embodiments this can be
accomplished using a combination of the pivot pin 460 and the inner
tube pin 470.
As shown in FIGS. 5A-5D, the opening 422 of each of the top jaw 402
and the bottom jaw 404 are aligned with the openings 242 on each of
the pair of arms of the yoke 240 of the outer tube 206. In some
embodiments, a pivot pin 460 is fitted through and secured to the
outer tube 206 such that the top jaw 402 and the bottom jaw 404 of
the jaw assembly 400 are retained between the yoke 240 of the outer
tube 206. The pivot pin 460 may also be configured to allow the top
jaw 402 and the bottom jaw 404 to rotate about the pivot pin
460.
As discussed above, the inner tube pin 470 can be configured to
cause the top jaw 402 and the bottom jaw 404 of the jaw assembly
400 to open and close. As shown in FIGS. 5A through 5D, the opening
342 in the pair of arms of the yoke 340 is aligned with the slot
244 in the pair of arms of the yoke 240. As illustrated in FIGS.
5B-5D, the ears 420 of the top jaw 402 and the bottom jaw 404 of
the jaw assembly 400 are located between the yoke 340, such that a
portion of the slot 424 intersects the plane on which the slot 244
of the outer tube 206 extends.
As better seen in the cross-sectional views in FIGS. 5B-5D, the
inner tube pin 470 can be fitted through and secured to each of the
openings 342. In some embodiments, the inner tube pin 470 is
press-fit into the bushing 480. In some embodiments, ends of the
inner tube pin 470 are configured to extend through the slot 244 of
the outer tube 206 such that the inner tube pin 470 can move freely
along the slots 424. The inner tube pin 470 can also be fitted
through each of the slots 424 of the ears 420 in the top jaw 402
and bottom jaw 404. This configuration can allow the inner tube 308
to advance or retract the inner tube pin 470 along the slot 244 as
the inner tube 308 can be advanced or retracted relative to the
outer tube 206. As the inner tube pin 470 moves along the length of
the slot 244, the inner tube pin 470 is configured to move along
the track of the slot 424 in each of the ears 420. As the inner
tube pin 470 moves in a first direction, the inner tube pin 470
moves to a first end of the slot 424, causing the jaw assembly 400
to open. Similarly, as the inner tube pin 470 moves in a second
direction, the inner tube pin 470 moves to a second end of the slot
424, causing the jaw assembly 400 to close.
In some embodiments, a wire guide 450 is configured to fit within
the outer tube 206 distal to the inner tube 308. The wire guide 450
may be configured to protect the wires located between the ears 420
of the jaws 402, 404 such that the wires are not impinged in the
jaws 402, 404. The wire guide 450 may include an opening to receive
the cable 440 and guide it along the length of the interior of the
inner tube 308. In some embodiments the wire guide 450 can be
comprised of a compliant material. For example, the material can be
a thermoplastic such as a resin polymer.
In some embodiments, the jaw assembly 400 includes a bushing 480.
As noted above, the bushing 480 can be located between the ears 420
of the top jaw 402 and the bottom jaw 404. The bushing 480 can be
configured to secure the pivot pin 460 in place and to maintain the
space between the ears 420 of the top jaw 402 and the bottom jaw
404. The bushing 480 can, for example, keep the ears 420 of the top
jaw 402 and the bottom jaw 404 separated such that the wires do not
get impinged. As well, the bushing 480 can be configured to retain
the draw pin 470. As discussed above, in some examples, the draw
pin 470 is pressed into the bushing 480. The bushing 480 may also
or alternatively be configured to prevent rotation of the top jaw
402 and the bottom jaw 404 within the jaw assembly 400. In some
embodiments, the bushing 480 can be comprised of a material such as
stainless steel.
FIG. 5E illustrates a cross-sectional view of the distal end 102 of
the therapeutic ultrasound device 100 through the pivot pin 460. As
illustrated, the plurality of ears 420 of the top jaw 402 and the
bottom jaw 404 are located between the pair of arms of the yoke 240
of the outer tube 206. In some embodiments, as discussed above, the
pivot pin 460 extends through the openings 422 in the top jaw 402
and the bottom jaw 404 to allow the pair of jaws to rotate. As
noted above, the wire guide 450 can be located near the base of the
yoke 240 and adjacent to the ears 420.
FIG. 5F illustrates a cross-sectional view of the distal end 102 of
the therapeutic ultrasound device 100 through the inner tube pin
470. As noted above, the inner tube pin 470 can extend through the
slot 244 of the outer tube 206 and through the distal end 302 of
the yoke 340. In some embodiments, the inner tube pin 470 also
extends through the slot 424 in each of the top jaw 402 and the
bottom jaw 404. A bushing 480 can be located between the ears 420
of the pair of jaws of the jaw assembly 400. As discussed, this can
help to maintain the space between the ears 420 of the pair of jaws
of the jaw assembly 400 and prevent rotation of the pair of jaws of
the jaw assembly 400.
The jaw assembly 400 can be configured such that both the top jaw
402 and the bottom jaw 404 are movable. In some embodiments, only
one of the pair of jaws of the jaw assembly 400 is movable. In some
embodiments, the top jaw 402 and bottom jaw 404 form an angle when
open and the movement of the top jaw 402 and the bottom jaw 404 is
a scissor-like movement. In other embodiments, the top jaw 402 and
the bottom jaw 404 are parallel to one another and open and close
such that the pair of jaws remain in parallel with one another.
Acoustic Stack
In some embodiments, the therapeutic ultrasound device 100 can
include an acoustic stack 500 within each jaw of the jaw assembly
400. In some embodiments, the jaw assembly 400 can include a jaw
with an acoustic stack 500 and a jaw without an acoustic stack.
FIGS. 6A-6C, 7A-7C, and 8A-8C illustrate a plurality of embodiments
of the acoustic stack 500.
FIGS. 6A-6C illustrate a first embodiment of an acoustic stack
500a. The acoustic stack 500a can include an acoustic wave
generating layer 510a layer, an adhesive 520a layer, and a matching
layer 540a. In some embodiments, the 510a layer is a piezoelectric
transducer (PZT). In some embodiments, the 510a layer can be a
capacitive machined ultrasound transducer (CMUT) or any other
silicon chip comprising machined drums that are configured to apply
a voltage and pulse. In some examples, the 510a layer can have a
width of 2.6 mm and a length of 15 mm.
In some examples, the matching layer 540a is configured to allow
the transmission of acoustic energy into a target site by matching
the acoustic wave propagation from the 510a layer (e.g., the PZT
layer) to the target tissue. As the frequency of the acoustic wave
is a function of the thickness and type of material passing through
it, the matching layer 540a is configured to prevent the wave from
getting reflected from the target tissue. In order for a wave to
propagate from one material to the next they should have similar
acoustic impedances. If there is an impedance mismatch the wave is
reflected. The degree of reflection depends on the degree of
mismatch.
One or more electrodes 530a can be located on an end of the
acoustic stack 500a between each layer of the PZT 510a, adhesive
520a, and matching layer 540a. In some embodiments, the electrodes
530a can comprise copper. In other embodiments the electrodes 530a
can comprise any conductive material. A cable 440 can be located on
an end of the acoustic stack 500a and electrically in contact with
the electrodes 530a to provide power to the acoustic stack 500a. In
some embodiments, as shown in FIG. 6C, the PZT 510a can include a
plurality of slots 512a. The slots 512a can be configured to
produce a more uniform acoustic field along the length of the
transducer 600a.
FIGS. 7A-7C illustrate a second embodiment of an acoustic stack
500b. As with the acoustic stack 500a, the acoustic stack 500b can
include a PZT 510b layer, an adhesive 520b layer, and a matching
layer 540b. One or more electrodes 530b can be located on an end of
the acoustic stack 500b between each layer of the PZT 510b,
adhesive 520b, and matching layer 540b. As with the acoustic stack
500a, a cable 440 can be electrically connected to the plurality of
electrodes 530b to provide power to the acoustic stack 500b.
FIGS. 8A-8C illustrate a third embodiment of an acoustic stack
500c. As discussed with regard to the acoustic stack 500a, 500b,
the acoustic stack 500c can include a PZT 510c layer, an adhesive
520c layer, and a matching layer 540c. As illustrated in FIG. 8C,
the PZT 510c layer can comprise a plurality of side-by-side PZTs.
In the example shown, the PZT 510c layer includes three (3)
adjacent PZTs. One or more electrodes 530c can be located in layers
above and below the PZT 510c layer. As shown in FIG. 8C, the
electrodes 530c can be aligned above and below the PZT 510c layer
such that each of the plurality of PZTs 510c are connected by an
electrode 530c. In some embodiments, as seen in FIG. 8C, the
adhesive 520c can be configured to receive a plurality of
electrodes 530c. A cable 440 can be electrically connected to at
least one of the plurality of electrodes 530c to provide power to
the acoustic stack 500c.
The matching layer 540 in each of the above-described embodiments
of the acoustic stack 500 can be configured to adapt the sound
speed of the PZT 510 with the sound speed through the tissue to
which the therapeutic ultrasound device is being applied, which
tissue may have a higher impedance. The matching layer 540 can
comprise graphite or fluoropolymer and the surface of the matching
layer 540 can be coated with parylene or any other material that
provides the matching layer 540 with a nonstick and/or
biocompatible surface.
In some embodiments, the matching layer 540 can be attached to the
surface of the PZT 510 with the adhesive 520 layer. The adhesive
520 layer can be an epoxy or a layer of metal formed from soldering
the PZT 510 to the matching layer 540.
As will be discussed in more detail below, each of the acoustic
stacks 500a, 500b, and 500c are configured to be secured in at
least one of the jaws 402, 404 of the jaw assembly 400. The
acoustic stack, when secured in the jaw 402, 404 forms a transducer
that can produce therapeutic ultrasound. As each of the acoustic
stacks 500a, 500b, 500c are simplistic in construction, the
transducer formed is capable of producing a higher intensity of
energy in comparison to other transducer constructions currently in
existence. In this way, the small size of the jaw assembly (e.g., 3
mm-15 mm) can efficiently seal and/or cut tissue.
Each of the acoustic stacks 500a, 500b, and 500c are configured to
provide the acoustic field and power described above. In some
embodiments, each of the acoustic stacks 500a, 500b, 500c provide
for varying resultant acoustic field maps when driven in water.
Each of the acoustic stacks 500a, 500b, and 500c differ in the
complexity in construction. In some examples, the acoustic stack
500b has the most simplistic construction compared to the
construction of the acoustic stack 500c.
Transducer and Relationship Between Applied Power and Force
In some examples, as discussed above, by placing the ultrasound
transducers on opposing arms of a clamp, we achieve a well-confined
and controlled high intensity region midline between the
transducers where the absorbed energy cauterizes the tissue
progressing from the midline toward the transducers resulting in a
complete plane of cauterization. Particularly where DTU is used,
significant collateral damage due to high focal gains and long
transmission paths through intervening tissue can be avoided and
instead provide for invasive or minimally-invasive procedures. The
use of DTU can provide the ability to induce planes of
cauterization/ablations to treat volumes (up to .about.30 cm.sup.3)
of tissue in seconds as opposed to the raster scanning technique
frequently required with transcutaneous HIFU. Existing raster
scanning can require long treatment times (e.g., hours) to ablate a
comparable volume as ablated using the presently disclosed
device.
In some embodiments, ablation occurs in seconds due to the heat
generation via ultrasound absorption and because the high intensity
region is well-contained within the midline of the transducer
heads. In the disclosed device, there is no collateral thermal
spreading beyond the region of interest, and the face of the
transducers does not heat excessively, thus preventing tissue
adhering to the applicator. Ablated tissue is resorbed by the body
similar. The disclosed device has a considerable advantage over
existing ablative technologies in that ablation and hemostasis can
be reached in significantly quicker treatment time and any
complications due to thermal spreading and tissue adherence to the
device are fully avoided. In conjunction with the innovative
therapy modality/device, ultrasound also affords the ability to
interrogate the treated region to evaluate the progression of the
therapy with the same transducers that are administering the
therapy.
In some embodiments, to provide treatment at a target site,
sufficient clamping force and power from the jaw assembly 400 must
be delivered. Particularly when the jaw assembly 400 is within the
3 mm-15 mm range, the configuration of the transducers of the jaw
assembly 400 can be relevant to providing sufficient power to the
target site.
In most constructions of transducers, the transducer includes a
backing layer, a copper electrode layer, a PZT layer, a second
copper electrode layer, and another backing layer. Each of these
layers, in particular the plurality of backing layers, provide an
increased resistance that limits the power that can be delivered by
the transducer. However, conventional transducers are built with
these components to form a transducer that can be operated over a
broad range of frequencies.
In contrast, the disclosed therapeutic ultrasound device 100
includes a transducer in the jaw assembly 400 that is constructed
to operate within a narrow range of frequencies so as to provide
for greater power/cm.sup.3. In some embodiments, the transducer can
be designed to work at any ultrasound frequency. For example, the
transducer can be designed to work between 1 MHz and 10 MHz. In
some embodiments, the disclosed transducer of the therapeutic
ultrasound device 100 is driven by a radio frequency (RF) signal
generator that produces between 10 W to 200 W of electricity. The
transducer of the therapeutic ultrasound device 100 is configured
to convert the electrical power into acoustic power. The disclosed
transducer of the therapeutic ultrasound device 100 is configured
to function at between 60%-80% efficiency. For example, the
acoustic power generated by the transducer is approximately 200
Watts. FIGS. 9A and 9B illustrate cross-sectional embodiments of
each of the pair of jaws 402, 404 that form transducer 600a and
transducer 600a. Each and/or both of these embodiments can be
formed within the jaw assembly 400.
FIG. 9A illustrates an embodiment of the transducer 600a in one or
both of the jaws 402, 404. As shown, the transducer 600a can
include an acoustic stack 500 located in the shell 432 of the jaws
402, 404. As discussed above, the acoustic stack 500 can comprise a
matching layer 540 and a PZT 510. In contrast to conventional
transducers that include a backing layer, the disclosed transducer
600a has an air-filled pocket 610 backing that is configured to
ensure high efficiency as ultrasound does not travel well through
air. The acoustic wave generating layer (e.g., PZT 510 layer), is
configured to generate acoustic waves through both sides of the 510
layer. As air is the greatest impedance mismatch possible for an
acoustic wave generator (e.g., PZT), the air-filled pocket 610
causes most of the acoustic wave to be reflected back on the
air-filled side and into the tissue.
As noted above, the present construction of the transducer does not
include the many layers present (e.g., the plurality of electrode
layers and backing layers) in conventional construction of
transducers. The embodiments of the transducer 600a therefore
encounters less impedance and can generate significantly more power
over a relatively short distance when compared to conventional
transducers. As well, the fewer layers included in a transducer
reduces the amount of loading the PZT layer experiences. This can
therefore enable the PZT layer to generate more acoustic power at a
given electrical power. This increased power, along with the force
that can be produced in the jaw assembly of the therapeutic
ultrasound device 100 disclosed above, can allow the relatively
small size of the jaw assembly 400 (e.g., 3 mm-15 mm) to seal
and/or cut tissue at a target location over a short amount of time.
The ability of the therapeutic ultrasound device 100 to seal and/or
divide tissue is a function of energy delivered to the tissue, the
pressure with which the tissue is clamped, and the amount of time
treatment is applied (e.g., Power=Energy/Time). An example of this
relationship is illustrated in FIG. 14.
FIG. 9B illustrates another embodiment of the transducer 600b that
can be formed in one or both of the jaws 402, 404. Similar to the
transducer 600a, the transducer 600b can include an acoustic stack
500 located in the shell 432 of the jaws 402, 404. As well, the
acoustic stack 500 can comprise a matching layer 540 and a PZT 510.
In addition to the air-filled pocket 610, the transducer 600b
includes a lining 620 that serves to further electrically isolate
the inside surface of the shell 432. As discussed with regard to
the air-filled pocket 610, the lining 620 is configured to further
improve the efficiency of the ultrasound. In some examples, the
lining 620 comprises a heat resistant polymer. In some embodiments,
the lining 620, by further electrically isolating the inside
surface of shell 432, further prevents the power generated from the
transducer from being dissipated. As noted above, this can increase
the power generated in the transducer 600b. Along with the force
that can be produced in the jaw assembly 400 of the therapeutic
ultrasound device 100 disclosed above, the configuration of the
transducer 600b can allow the relatively small size of the jaw
assembly 400 (e.g., 3 mm-15 mm) to seal and/or cut tissue at a
target location over a short amount of time. As discussed above,
the ability of the therapeutic ultrasound device 100 to seal and/or
divide tissue is a function of energy delivered to the tissue, the
pressure the tissue is clamped with, and the amount of time
treatment is applied (e.g., Power=Energy/Time).
In some embodiments, when the jaw assembly 400 of the therapeutic
ultrasound device 100 engages a target site, the transducer 600a,
600b can launch an acoustic wave toward the target site in a medium
(e.g., tissue) and receive echoes as the acoustic wave reflects off
the tissue. For example, a wavelength of 0.15 mm can be produced
using 10 MHz, a wavelength of 0.3 mm can be produced using 5 MHz, a
wavelength of 0.4 mm can be produced using 3.5 MHz, and a
wavelength of 1.5 mm can be produced using 1 MHz. In some examples,
the target site may be diseased or not diseased tissue, muscle,
vasculature, etc. In some examples, the transmitted ultrasound
waves can become nonlinear as they propagate through the tissue,
and the nonlinear propagation can generate harmonics in the
acoustic beam that develop at or near the focal region of the
transducer 600a, 600b from which they are transmitted. In some
embodiments, at the focal region, the harmonic content can cause
acoustic beam narrowing, enhanced tissue heating and proximal focal
shifts. In some examples, the focal region can refer to a point,
area, or volume at which the intensity of the transducer 600a, 600b
source is the highest.
As illustrated in FIGS. 14A-14D, the tissue can be heated to
between 40.degree. C. and 100.degree.. As illustrated in FIG. 11,
the velocity of sound in tissue is temperature dependent. As the
tissue temperature increases to approximately 50.degree. C.,
protein denaturation occurs and results in an inflexion point in
the slope of the sound velocity vs. temperature plot. Near
50.degree. C., the slope can be zero.
FIG. 12A illustrates that the relationship between maximum
temperature and acoustic energy followed a power law relationship
versus intensity with time fixed, FIG. 12B illustrates a linear
relationship versus time with power and intensity fixed, and FIG.
12C illustrates a linear relationship versus intensity at a fixed
time. These preliminary trends can be configured to predict the
energy, time, and intensity required to achieve desired
temperatures. FIG. 12D further indicates the time required to reach
a given temperature at a specific power.
In some examples, the jaw assembly 400 is configured to monitor the
power that is reflected back as the ultrasound is passed through
the target site. In some embodiments, the power reflected back can
help the therapeutic ultrasound device 100 to determine the degree
in which target site has been cauterized (e.g., sealed or cut). In
some examples, this can be determined, over time, as tissue is
being cauterized and the acoustic impedance changes. This change in
impedance can affect the amount of power reflected back and sensed
by the jaw assembly 400.
In some embodiments, the therapeutic ultrasound device 100 can
sense (e.g., significant) change in the voltage standing wave ratio
(VSWR) between the two transducers in the jaw assembly 400 as an
indicator for ending of therapy, which is defined as complete
ablation and hemostatic control. In vivo experiments were conducted
in which the jaw assembly 400 was positioned on porcine kidneys
which were instrumented with thermocouples. Therapy was
administered until a significant change in VSWR was observed
(average time of approximately 140 seconds). Upon resection of the
distal portion of the kidney, no bleeding was observed (immediately
after and for a 10-minute time frame) and the ablation plane was
clearly and completely demarked. Furthermore, treatment times
exceeding the VSWR inflexion point did not show excessive heating
adjacent to the clamp heads. The results of these studies confirmed
that VSWR is a potentially viable mechanism for determining
end-of-treatment time thus ensuring robust ablation and hemostasis
while at the same time avoiding overtreatment and possible
collateral damage due to thermal spread.
FIGS. 13A-13D illustrate the use of VSWR to determine end of
treatment. Turning first to FIG. 13A, an inflection point is
observed in treatments in which 43.degree. C. was exceeded. FIG.
13B illustrates that extended treatments (e.g., 240s) indicated a
slight elevation in temperatures adjacent to the clamp as opposed
to significant temperature increases in the focal region. FIG. 13C
illustrates an example of where using the VSWR to determine the end
of therapy in vivo results in complete hemostasis. Lastly, FIG. 13D
illustrates that internal temperature reached approximately
50.degree. C. at 140s during in vivo experiments.
In some examples, in addition to the ultrasound generated by the
transducer 600a, 600b, the force applied by the jaw assembly 400
can be effective in sealing and/or cutting the target tissue. In
some embodiments, particularly with vessel sealing, there exists a
relationship between the clamping force applied by the jaw assembly
400 and the power required. An example of the relationship is
illustrated in FIG. 14. For example, when the clamping force
applied by the jaw assembly 400 is too low, a higher energy from
the transducer 600a, 600b is required and vice versa.
In some embodiments, as discussed above, the jaw assembly 400 can
be configured to provide 10 lbs. of clamping force. In some
embodiments, this can range between 10-14 lbs. of clamping force at
the jaw assembly 400. In some embodiments, the clamping force at
the jaw assembly 400 can be less than 10 lbs., between 10-11 lbs.,
between 11 lbs.-12 lbs., between 12 lbs.-13 lbs., between 13
lbs.-14 lbs., or greater than 14 lbs. In some embodiments, the
clamping force at the jaw assembly 400 can be any of 10 lbs., 11
lbs., 12 lbs., 13 lbs., or 14 lbs. In order to generate the
aforementioned clamping force in the jaw assembly 400--particularly
when the top jaw 402 and the bottom jaw 404 have a width of only 3
mm-10 mm--sufficient force must be applied at the handle 120 of the
therapeutic ultrasound device 100. In some embodiments, the ratio
of the transfer of force is about 20:1. In some examples, the ratio
of the transfer of force is between 15:1 to about 20:1; the ratio
is 15:1, 16:1, 17:1, 18:1, 19:1, or 20:1; or the ratio is between
15:1 and 16:1, the ratio is between 16:1 and 17:1, the ratio is
between 17:1 and 18:1, the ratio is between 18:1 and 19:1, or the
ratio is between 19:1 and 20:1. In some embodiments, the ratio of
the transfer of force satisfies the FDA requirement wherein 95% of
the female population can actuate the therapeutic ultrasound device
100. In some examples, the combination of the pivot pin 460 and the
angle and/or curvature of the slot 424 on the ears 420 of the pair
of jaws 402, 404 are configured to increase the moment on the jaw
assembly 400 to help increase the force generated at the jaw
assembly 400.
FIG. 10 illustrates the relationship between the clamping force
generated by the jaw assembly 400 versus the jaw opening angle for
a straight slot 424 compared to a curved slot 424 in the ears 420
of the pair of jaws 402, 404. As shown in FIG. 10, a straight slot
424 can provide a jaw clamp force that ranges between approximately
5.0 lbs. and 6.8 lbs. over a range of approximately 25 to 0
degrees. In another example, a straight slot 424 can provide a jaw
clamp force that ranges between approximately 7.50 lbs. and 8.50
lbs. over a range of approximately 15 to 0 degrees. By comparison,
a curved slot 424 can provide a jaw clamp force that ranges between
2 lbs. and 10 lbs. over a range of 15 to 0 degrees. As illustrated,
a curved slot 424 can be configured to generate a moment to provide
a greater jaw clamping force over a smaller range of angles.
In addition to the force applied by the jaw assembly 400 and the
power generated by the transducer 600, the time in which the jaw
assembly 400 is applied to the target tissue can affect whether the
tissue and/or vessel is sealed or cut. In some embodiments the
Energy to seal is a function of clamping pressure, acoustic power,
and time: E(s)=F(cp(t),ap(t))
In some embodiments, tissue and/or vessels can be sealed within
approximately 2 seconds. In some examples, tissue and/or vessels
can be cut within approximately 10 seconds. This time is in
contrast to thermal or RF technology which requires approximately
10 to 25 seconds for comparable tissue. As well, use of ultrasound
in the transducer 600 can provide for controlled tissue sealing
and/or cutting within a very short time frame. In some examples,
the transducer 600 can seal and/or cut tissue within 2 to 10
seconds, depending on the tissue. For example, a 5 mm vessel can be
sealed using 100 Joules of acoustic energy. Similarly, the 5 mm
vessel can be cut with an additional 50 Joules of acoustic energy.
In some embodiments, a 5 mm vessel requires about 270 Joules to
seal. In some examples, a 5 mm vessel requires about 640 Joules to
divide. The amount of energy required will vary depending on tissue
type and vessel size as well as the acoustic regime used to treat
the target tissue.
Certain Terminology
Terms of orientation used herein, such as "top," "bottom,"
"horizontal," "vertical," "longitudinal," "lateral," and "end" are
used in the context of the illustrated embodiment. However, the
present disclosure should not be limited to the illustrated
orientation. Indeed, other orientations are possible and are within
the scope of this disclosure. Terms relating to circular shapes as
used herein, such as diameter or radius, should be understood not
to require perfect circular structures, but rather should be
applied to any suitable structure with a cross-sectional region
that can be measured from side-to-side. Terms relating to shapes
generally, such as "circular" or "cylindrical" or "semi-circular"
or "semi-cylindrical" or any related or similar terms, are not
required to conform strictly to the mathematical definitions of
circles or cylinders or other structures, but can encompass
structures that are reasonably close approximations.
Conditional language, such as "can," "could," "might," or "may,"
unless specifically stated otherwise, or otherwise understood
within the context as used, is generally intended to convey that
certain embodiments include or do not include certain features,
elements, and/or steps. Thus, such conditional language is not
generally intended to imply that features, elements, and/or steps
are in any way required for one or more embodiments.
Disjunctive language such as the phrase "at least one of X, Y, or
Z," unless specifically stated otherwise, is otherwise understood
with the context as used in general to present that an item, term,
etc., may be either X, Y, or Z, or any combination thereof (e.g.,
X, Y, and/or Z). Thus, such disjunctive language is not generally
intended to, and should not, imply that certain embodiments require
at least one of X, at least one of Y, or at least one of Z to each
be present.
The terms "approximately," "about," and "substantially" as used
herein represent an amount close to the stated amount that still
performs a desired function or achieves a desired result. For
example, in some embodiments, as the context may dictate, the terms
"approximately," "about," and "substantially" may refer to an
amount that is within less than or equal to 10% of the stated
amount. The term "generally" as used herein represents a value,
amount, or characteristic that predominantly includes or tends
toward a particular value, amount, or characteristic. As an
example, in certain embodiments, as the context may dictate, the
term "generally parallel" can refer to something that departs from
exactly parallel by less than or equal to 20 degrees.
Unless otherwise explicitly stated, articles such as "a" or "an"
should generally be interpreted to include one or more described
items. Accordingly, phrases such as "a device configured to" are
intended to include one or more recited devices. Such one or more
recited devices can also be collectively configured to carry out
the stated recitations. For example, "a processor configured to
carry out recitations A, B, and C" can include a first processor
configured to carry out recitation A working in conjunction with a
second processor configured to carry out recitations B and C.
The terms "comprising," "including," "having," and the like are
synonymous and are used inclusively, in an open-ended fashion, and
do not exclude additional elements, features, acts, operations, and
so forth. Likewise, the terms "some," "certain," and the like are
synonymous and are used in an open-ended fashion. Also, the term
"or" is used in its inclusive sense (and not in its exclusive
sense) so that when used, for example, to connect a list of
elements, the term "or" means one, some, or all of the elements in
the list.
Overall, the language of the claims is to be interpreted broadly
based on the language employed in the claims. The language of the
claims is not to be limited to the non-exclusive embodiments and
examples that are illustrated and described in this disclosure, or
that are discussed during the prosecution of the application.
Summary
Although various covers have been disclosed in the context of
certain embodiments and examples (e.g., surgical assemblies and
methods), this disclosure extends beyond the specifically disclosed
embodiments to other alternative embodiments and/or uses of the
embodiments and certain modifications and equivalents thereof. For
example, any of the disclosed covers can be used on the leading
edge of other types of devices, such as wings, vanes, blades,
propellers, impellers, or otherwise. Various features and aspects
of the disclosed embodiments can be combined with or substituted
for one another in order to form varying modes of the conveyor. The
scope of this disclosure should not be limited by the particular
disclosed embodiments described herein.
Certain features that are described in this disclosure in the
context of separate implementations can also be implemented in
combination in a single implementation. Conversely, various
features that are described in the context of a single
implementation can also be implemented in multiple implementations
separately or in any suitable sub-combination. Although features
may be described above as acting in certain combinations, one or
more features from a claimed combination can, in some cases, be
excised from the combination, and the combination may be claimed as
any sub-combination or variation of any sub-combination.
Moreover, while operations may be depicted in the drawings or
described in the specification in a particular order, such
operations need not be performed in the particular order shown or
in sequential order, and all operations need not be performed, to
achieve the desirable results. Other operations that are not
depicted or described can be incorporated in the example methods
and processes. For example, one or more additional operations can
be performed before, after, simultaneously, or between any of the
described operations. Further, the operations may be rearranged or
reordered in other implementations. Also, the separation of various
system components in the implementations described above should not
be understood as requiring such separation in all implementations,
and it should be understood that the described components and
systems can generally be integrated together in a single product or
packaged into multiple products. Additionally, other
implementations are within the scope of this disclosure.
Some embodiments have been described in connection with the
accompanying figures. The figures are drawn and/or shown to scale,
but such scale should not be limiting, since dimensions and
proportions other than what are shown are contemplated and are
within the scope of the present disclosure. Distances, angles, etc.
are merely illustrative and do not necessarily bear an exact
relationship to actual dimensions and layout of the devices
illustrated. Components can be added, removed, and/or rearranged.
Further, the disclosure herein of any particular feature, aspect,
method, property, characteristic, quality, attribute, element, or
the like in connection with various embodiments can be used in all
other embodiments set forth herein. Additionally, any methods
described herein may be practiced using any device suitable for
performing the recited steps.
In summary, various embodiments and examples of leading edge
assemblies have been disclosed. Although the assemblies have been
disclosed in the context of those embodiments and examples, this
disclosure extends beyond the specifically disclosed embodiments to
other alternative embodiments and/or other uses of the embodiments,
as well as to certain modifications and equivalents thereof. This
disclosure expressly contemplates that various features and aspects
of the disclosed embodiments can be combined with, or substituted
for, one another. Thus, the scope of this disclosure should not be
limited by the particular disclosed embodiments described above,
but should be determined only by a fair reading of the claims that
follow.
* * * * *